Is there any relationship between agronomic traits, soil properties and essential oil profile of peppermint (Mentha piperita L.) treated by fertiliser treatments and irrigation regimes?

Abstract

AbstractOne of the greatest challenges in recent years is providing enough food to feed the increasing world population, with limited freshwater resources. However, effective fertiliser management also has a fundamental role to improve yield quality and quantity. Organic fertiliser not only supplements nutrients but also improves physicochemical and biological soil properties. A 2‐year field experiment was conducted to examine the influence of urea and vermicompost fertiliser on oil phytochemical properties of peppermint pH, soil cation exchange capacity (CEC) and organic carbon of experimental site under three irrigation regimes in 2018 and 2019. The experiments had three water deficit regimes (no stress, moderate, and severe drought stress) as a main plot. The subplot division consisted of six fertiliser treatments: unfertilised (control); 140 kg urea ha−1; 105 kg urea ha−1 + 3.3 ton vermicompost ha−1; 70 kg urea ha−1 + 6.6 ton vermicompost ha−1; 35 kg urea ha−1 + 10 ton vermicompost ha−1; and 13.5 ton vermicompost ha−1. The maximum leaf area index (4.29) and dry matter weight (3,803 kg ha−1) were observed in control irrigation, while the highest essential oil content (0.97%) could be seen under mild water deficit stress. Additionally, the highest organic carbon and CEC were obtained under well‐watered conditions at 1.20% and 6.41 (meq 100 g soil−1), respectively. Dry matter weight and essential oil content increased considerably in response to increasing vermicompost in fertiliser treatments, and the highest content of these traits were observed in 2019 and with 13.5 ton vermicompost ha−1. The menthol content increases in response to deficit irrigation and integrated fertiliser. These data indicate that mild drought stress can increase the synthesis of medical compounds and vermicomposting can alleviate the impact of drought by conserving soil moisture as an acclimation mechanism to improve nutrient uptake and avoid yield losses.